The new species has a long, black tail and a five-toed foot, also black. The fur around its eyes and rump is yellow-orange, helping distinguish it from other species.

Marsupials in this genus are promiscuous maters. Females give birth to large broods that include offspring from several fathers. To raise their chances of siring more offspring, males mate for hours at a time with many females, Baker said. This sex bacchanalia sends the animals' stress hormone levels skyrocketing, which eventually results in death.

Females collect sperm from their doomed mates all breeding season and then ovulate, allowing for the fertilization of many half-siblings all at once. Some females survive to breed multiple times, but most die after their first litter is weaned.